Ofcourse this is possible! The basic idea behind this is to install multiple Odoo instances on multiple locations. I've made an installation script that does all of this and which works fully automated. See: https://github.com/Yenthe666/InstallScript/

This would install and configure three different Odoo code bases. You can even choose which version of Odoo you would like on this line: https://github.com/Yenthe666/InstallScript/blob/9.0/odoo_install.sh#L29 The different Odoo's would be under /yyysiteone/yyysiteone-server, yyysiteone/yyysiteone-server and under /sitetwo/sitetwo-server.The only thing that is not included in my script is db-filter and forwarding to a correct URL.There are some topics about this on the help forum too though! The main idea is to redirect your internal Odoo to the webhosting with pointers. You could do this with Nginx and your hosting provider for example.